Published models for the Proterozoic McArthur Basin show up to 4 km of sedimentary cover over widespread shelves, and a 50-80 km wide by 600 km long, central meridional half-graben, the Batten Trough, in which up to 10 km of cover is preserved. This model is supported and extended herein by basin-wide interpretation of gravity and magnetic anomalies. The margins of the area of thick cover correlate with steep gravity and/or magnetic anomaly gradients. The dominant rock types in this cover are identified from their combined gravity and magnetic signatures. Estimates of depth to magnetic basement are combined with geological constraints to map the basement configuration throughout the basin. The predicted form of the Batten Trough is essentially confirmed, and concealed extensions outlined beneath the Gulf of Carpentaria. However, it is now shown that this trough is separated into two distinct structures by the Urapunga Tectonic Ridge, and it is now redefined as the Batten Trough (south only) and Walker Trough (north). The concealed Beetaloo Sub-basin of thick Roper Group, in the southwest, and possible adjacent troughs of McArthur Group carbonates, represent the subsurface link between the McArthur Basin and Tomkinson Creek beds. An east-west extension model, related to block rotation and accommodation by northwest transfer faults, is invoked to explain the evolution of the several rifts in the basin. Later deformation has modified these structures and reversed many of the earlier displacements.